Cancer morbidity among Danish male urban bus drivers: A historical cohort study

To investigate whether urban bus drivers are at increased risk for cancer.

Urban bus drivers in a cohort established in 1978 in the three largest cities of Denmark were followed-up in the Danish Cancer Registry until the end of 2003, and relative risks for cancers were estimated.

Of 2,037 men included 70% reported in 1978 that they smoked. The standardized incidence ratio (SIR) for cancer in comparison with that of other male residents of the three cities was 1.09 [1.0-1.2]. The excess was due mainly to increased risks for cancers of the bladder (SIR, 1.6; 1.2-2.0) and lung (1.2; 1.0-1.4). In an analysis with internal comparisons and adjustment for smoking, we found no significant associations between duration of employment and increased risks for cancers at these two sites.

In this long-term follow-up study we found little evidence of a causal association between employment as an urban bus driver in Denmark and subsequent cancer.